While John’s story is reaching audiences around the world, a change in attitudes is also being witnessed at home.
Dottie Achenbach, who is played by Maxine Peake in I Swear, has supported John since he was a teenager and regularly accompanies him to hospital appointments.
She said: “When we went before you would have all these people outside the entrance, and when John would tic you would get all these tuts and people approaching us in an angry way.
“They didn’t have the understanding.
“See now, we get out the car and minute he tics everyone turns around and shakes his hand and says things like: ‘well done’.
“What a difference the film has made.”